Monitoring or tracking eye movements and detecting a person's gaze point can be used in many different contexts. Eye tracking data can be an important information source in analysing the behaviour or consciousness of the person. It can be used both for evaluating the object at which the person is looking and for evaluating the respective person. The diverse uses of gaze point detection include studies on the usability of software and different types of interfaces; evaluation of web pages, advertising and advertisements; provision of means for educating pilots in simulator environments and for training surveillance personnel in security-critical roles; and research in psychology, behavioural sciences and human perception. A field which has attracted an increasing interest in recent years is the evaluation of advertising and other marketing channels.
Eye tracking techniques can also be used for interaction: a user can control a computer by just looking at it. Eye control can be applied as sole interaction technique or combined with keyboard, mouse, physical buttons and voice. Eye control is used in communication devices for disabled persons and in various industrial and medical applications.
While eye tracking systems are utilised in a growing range of applications, they are not yet flexible enough to belong to the standard equipment of new laptops and desktops although web cameras do. Most standard-type web cameras, having a resolution of a few million pixels, would provide sufficient optical quality for eye-tracking purposes. If needed, it is easy to provide supplementary illuminators around or behind the display screen (cf. applicant's co-pending European Patent Applications EP 09 157104 and EP 09 157106, which are included herein by reference in their entirety), possibly as detachable units. However, the computational complexity of eye tracking may be enough to dissuade a computer vendor from including such capabilities, as some eye tracking implementations occupy a large part of the input/output capacity, memory resources and data processing capacity of the central processing unit (CPU) when run on a personal computer in real time. Such occupancy is detrimental to other functions of the computer; notably it may slow down execution of other processes and increase their latency. Thus, there is a need for improved computer implementations of eye tracking.